1. Field of the Invention
This invention relates to a hydraulic cylinder assembly with a liquid recovery system and is more particularly concerned with a hydraulic fluid recovery system for the hydraluic cylinder of a hydraulic elevator.
2. Description of the Prior Art
In the past, elevators or lifts which move only a few floors have been operated by hydraulics through the use of long piston rods connected to the bottoms of the elevator cars and retractable and extendable in hydraulic cylinders. Usually there is some leakage of the hydraulic fluid around the piston at the packing gland or gland box, such leaked liquid, in the past, has been drained to an open can which is emptied, periodically. At times, of course, the hydraulic fluid spills onto the floor supporting the hydraulic cylinder.
In the prior art is the patent to Persons, U.S. Pat. No. 1,787,700 which disclose a recriprocating piston and piston rod for a pump, the piston rod being enclosed by a bellows surrounding the piston rod. One end of the bellows is reciprocated by the piston and the other end is connected to a stationary cap. A passageway leads from the low pressure side of the piston to the bellows and a bleeder passageway leads from this low pressure side through a ball check valve which permits fluid from the low pressure side to be received in an intake passageway during an intake stroke of the piston. A second ball check valve permits discharge by the piston of this fluid into the discharage pipe when the piston is recriprocated. The Persons structure is not suitable for pistons having a long stroke or for hydraulic pistons which act as motors, rather than pumps and in which no vacuum is drawn on the high pressure side of the piston.